Astronauts say it is the most-asked question they get from people. There have been books written about it. Maybe because we all have to do it, everyone wants to know how it works in zero-gravity. This past weekend I gave a presentation to about 60 Girl Scouts about living and working in space, and I knew this question was going to come up. It did, and with this video, I was prepared. Here, Canadian astronaut Chris Hadfield eloquently gives the best description ever of how it works to go to the bathroom in space. And he tells all in less than two minutes, too.